Plasmonic Enhancement in the Fluorescence of Organic and Biological Molecules by Photovoltaic Tweezing Assembly

The potential of photovoltaic tweezers to produce plasmonic platforms for fluorescence enhancement of organic or biological molecules is demonstrated. 1D and 2D patterns of silver nanoparticles are produced on the surface of LiNbO3:Fe substrates using this photovoltaic tool, which allows depositing in parallel a large number of particles in accordance with imposed 1D and 2D light profiles. The nanoparticle patterns reveal a variety of plasmonic features whose resonances cover a broad spectral range and are able to produce efficient fluorescence enhancement. First, a remarkable average enhancement factor of ten is measured for Disperse Red 1 organic molecules deposited on the patterns. Clear enhancements are also obtained from fluorescein labeled biological molecules (DNA and asynthetic peptide). Finally, the possibility of using the photoelectrically generated metallic patterns with other substrates is also demonstrated by enhancement experiments for which the nanoparticle pattern is transferred to a non-photovoltaic substrate.